The three described specific aims and approach to their accomplishment in this proposal are: 1) to determine the importance of opioid-receptor interaction on homeostatic cellular renewal of the diabetic corneal epithelium by studying OGF/receptor expression and the effects of excess OGF or blockade of OGF activity with naltrexone on DNA synthesis in diabetic rat corneal epithelium limbus and conjunctiva; 2) to define the role of an endogenous opioid system related to growth in the re-epithelialization of denuded corneal epithelium in diabetic rats by examining healing and integrity of the repaired epithelium after systemic and topical treatment with naltrexone of rats subjected to corneal abrasions; and 3) to ascertain the influence of an endogenous opioid system related to growth in the repair of corneal wound healing by studying the effect of opioid receptor blockade on healing of wounded epithelium in human corneas in organ culture.